CN211648650U - Multi-stage oil cylinder and engineering machinery with same - Google Patents

Abstract

The utility model provides a multistage hydro-cylinder and engineering machine who has it, including cylinder body and N level piston assembly, it has along its axially extended cavity to inject in the cylinder body, the cavity has the open end, in the N level piston assembly, N is more than or equal to 2's integer, first level piston assembly is equipped with first pole chamber and first no pole chamber, first pole chamber cooperatees so that first level piston assembly's piston rod stretches out or the withdrawal open end with first no pole chamber, M level piston assembly is equipped with M has pole chamber and M no pole chamber, wherein M is less than or equal to N's integer, M has pole chamber and M no pole chamber to cooperate so that M level piston assembly's piston rod stretches out or the withdrawal open end, first no pole chamber and M no pole chamber interval distribution and each other intercommunication, first pole chamber and M have pole chamber interval distribution and each other not intercommunication. The multistage oil cylinder is convenient in mold changing, accurate in positioning, compact in structure and small in installation space.

Description

Multi-stage oil cylinder and engineering machinery with same

Technical Field

The utility model belongs to the technical field of mechanical hydraulic pressure, especially, relate to multistage cylinder and engineering machine tool who has it.

Background

Some equipment has compact structure and limited installation space, needs the oil cylinder to have the size as small as possible, and needs the oil cylinder to realize various actions. For example, a mold frame moving oil cylinder of an extruder needs to lift a mold frame to a designated position by the oil cylinder, then mold changing is carried out, and after the mold changing is completed, the mold needs to be lifted to another designated working position. A general mould frame moving oil cylinder adopts a multi-stage oil cylinder, each stage is shared by an oil outlet path, and a displacement sensor is adopted to detect the real-time position of a piston rod. Or two single-stage oil cylinders are separately controlled.

However, the existing oil cylinder device has many defects in the using process: firstly, the precision of the lifting position is difficult to control due to the multi-stage oil cylinders shared by the oil inlet and outlet paths of each stage of oil cylinder, namely, after the first and second oil cylinders lift the mould moving frame to the designated position, the third stage piston rod is kept still theoretically, but the system continues to supply oil and pressurize to the oil cylinder, so that the third stage oil cylinder piston rod continues to extend outwards, the mould can not be changed, and at this time, the real-time position of each stage piston rod needs to be monitored by means of a displacement sensor, but the cost of the scheme is higher; secondly, if two single-stage oil cylinders are separately controlled to solve the defect, if one oil cylinder lifts the die frame to a specified position, die changing is carried out, and after the die changing is finished, the other oil cylinder lifts the die to a specified working position.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that exists among the prior art at least.

In view of this, the utility model provides a multistage cylinder, this multistage cylinder retooling is convenient, and the location is accurate, compact structure simultaneously, and installation space is little.

The utility model also provides an engineering machine tool with multi-stage cylinder, this engineering machine tool convenient to use, occupation space is little.

According to the utility model discloses multistage hydro-cylinder of first aspect embodiment, include: a cylinder defining a chamber therein extending axially therealong, the chamber having an open end; the piston assembly comprises a cavity, an N-stage piston assembly, a first rodless cavity, an M-stage piston assembly, an M-stage rodless cavity, a first rodless cavity and a second rodless cavity, wherein the N is an integer larger than or equal to 2, the N-stage piston assembly is arranged in the cavity and comprises a first-stage piston assembly and an N-stage piston assembly which are sequentially nested from outside to inside, the first-stage piston assembly is provided with the first rodless cavity and the first rodless cavity, the first rodless cavity is matched with the first rodless cavity so that a piston rod of the first-stage piston assembly extends out or retracts into the opening end, the M-stage piston assembly is provided with the M-stage rodless cavity and the M-stage rodless cavity, M is an integer smaller than or equal to N, the M-stage rodless cavity is matched with the M-stage piston assembly so that a piston rod of the M-stage piston assembly extends out or retracts into the opening end, the first rodless cavity and the M-stage piston assembly are respectively communicated with two rodless cavity oil passages, and are respectively communicated with two oil passages with rod cavities which are distributed at intervals.

According to the utility model discloses multistage cylinder, through setting up N level piston assembly and making first rodless chamber and M rodless chamber spaced apart distribution, and first there is the pole chamber and M to have pole chamber spaced distribution and respectively with spaced distribution have pole chamber oil circuit intercommunication, effectively distinguish multistage oil circuit, like this in the use, after first order piston rod is overhanging to be removed the frame with the mould and lift the assigned position, M level piston rod keeps the normal position motionless, do not need displacement sensor to monitor every level piston rod real-time position, be favorable to accurate positioning and the retooling cost is lower.

The carrier for aerosol products according to embodiments of the present invention may also have the following additional technical features:

according to the utility model discloses an embodiment, N is the integer that is more than or equal to 3, N level piston assembly is including being located first order piston assembly with S level piston assembly between the M level piston assembly, wherein 1 < S < M, S level piston assembly is equipped with S and has the pole chamber, S have the pole chamber with first have pole chamber intercommunication and with M has pole chamber spaced apart distribution, first have the pole chamber with S has the pole chamber all with same have pole chamber oil circuit intercommunication, S level piston assembly with first level piston assembly shares first rodless chamber.

According to an embodiment of the present invention, N is equal to M, the M-th stage piston assembly is a third stage piston assembly, the M-th rod cavity is a third rod cavity, the M-th rodless cavity is a third rodless cavity, the S-th stage piston assembly is a second stage piston assembly, the S-th rod cavity is a second rod cavity, one end of the first stage piston assembly is inserted into the cavity and is movable along the axial direction thereof, the first rod cavity is fitted between the outer wall surface of the piston rod of the first stage piston assembly and the inner wall surface of the cylinder body, and the first stage piston assembly is provided with a first passage extending along the axial direction thereof; the multistage hydro-cylinder still includes: the inner cylinder barrel is inserted in the first channel and extends axially along the first channel, the inner cylinder barrel is provided with a second channel extending axially along the inner cylinder barrel, the second channel is internally inserted with a second-stage piston assembly capable of moving axially along the second channel, the first rodless cavity is defined between the piston end of the second-stage piston assembly and the inner wall surface of the inner cylinder barrel in a matching manner, the second rod cavity is defined between the outer wall surface of the piston rod of the second-stage piston assembly and the inner wall surface of the inner cylinder barrel in a matching manner, the second-stage piston assembly is provided with a third channel extending axially along the second-stage piston assembly, the third-stage piston assembly capable of moving axially along the third channel is inserted in the third channel, the third rod cavity is defined between the outer wall surface of the piston rod of the third-stage piston assembly and the inner wall surface of the second-stage piston assembly in a matching manner, and the third rod cavity is defined between the piston end of the third-stage piston assembly and the inner wall surface Three rodless cavities.

According to an embodiment of the present invention, the cylinder body is provided with an oil passage communicating with the first rod-less chamber.

According to the utility model discloses embodiment multistage cylinder, still include: the first guide sleeve is arranged at the opening end and is provided with a first mounting hole which is communicated along the axial direction of the cavity, one end of the first-stage piston assembly penetrates through the first mounting hole and extends into the cavity, a first oil port and a second oil port are arranged on the first guide sleeve, the first oil port is communicated with the rodless cavity oil way corresponding to the first rodless cavity, and the second oil port is communicated with the first rod cavity and the second rod cavity respectively.

According to the utility model discloses an embodiment, with first rodless chamber corresponds be equipped with at least partly on the rodless chamber oil circuit with the axis parallel first through-hole of cavity.

According to an embodiment of the present invention, the piston rod of the third stage piston assembly is provided with a second through hole running through in the axial direction thereof, the second through hole being formed to correspond to the third rodless cavity at least a part of the rodless cavity oil passage.

According to the utility model discloses multistage hydro-cylinder, its characterized in that still includes: the second guide sleeve is arranged at the opening end of the cavity and is provided with a second mounting hole which is communicated along the axial direction of the cavity, one end of a piston rod of the third-stage piston assembly penetrates through the second mounting hole and extends into the third channel, and a third oil port communicated with the third rod cavity is formed in the second guide sleeve.

According to the utility model discloses multistage hydro-cylinder, its characterized in that still includes: the flange is arranged on one side, back to the cylinder body, of the second guide sleeve and is provided with a third mounting hole which is communicated along the axial direction of the cavity, one end of a piston rod corresponding to the third-stage piston assembly sequentially penetrates through the third mounting hole and the second mounting hole and then extends into the third channel, and a fourth oil port is formed in the flange and is communicated with the second through hole.

According to the utility model discloses engineering machine tool of second aspect embodiment includes the multistage hydro-cylinder of any one of above-mentioned embodiment.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a structural section view of a multi-stage cylinder according to an embodiment of the present invention.

Fig. 2 is a left side view of a multi-stage cylinder according to an embodiment of the present invention.

Fig. 3 is a partial cross-sectional view of a multi-stage cylinder according to an embodiment of the present invention.

Reference numerals:

a multi-stage cylinder 100;

a cylinder body 10; a chamber 11;

a first stage piston assembly 20; a first rod chamber 21; a first rod chamber 22; a first through hole 23; a first channel 24;

the S-stage piston assembly 30; the S-th rod cavity 31; a third channel 33;

an M-th stage piston assembly 40; the Mth rod chamber 41; the Mth rodless cavity 42; a second through hole 43;

an inner cylinder tube 50; a second channel 51;

a first guide sleeve 60; a first oil port 62; a second oil port 63;

a second guide sleeve 70; a third oil port 72;

a flange 80; a fourth oil port 81.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present invention, and should not be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship indicated based on the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention. Furthermore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The multi-stage cylinder 100 according to the embodiment of the present invention will be described first.

As shown in fig. 1 to 3, a multistage cylinder 100 according to an embodiment of the present invention includes a cylinder body 10 and an N-stage piston assembly.

Specifically, a chamber 11 extending along an axial direction of the cylinder 10 is defined in the cylinder 10, the chamber 11 has an open end, N is an integer greater than or equal to 2 in an N-stage piston assembly, the N-stage piston assembly is disposed in the chamber 11 and includes a first-stage piston assembly 20 to an N-stage piston assembly nested from outside to inside, the first-stage piston assembly 20 is disposed with a first rod chamber 21 and a first rodless chamber 22, the first rod chamber 21 is matched with the first rodless chamber 22 to extend or retract a piston rod of the first-stage piston assembly 20 to the open end, the M-stage piston assembly 40 is disposed with an M-th rod chamber and an M-th rodless chamber 42, M is an integer less than or equal to N, the M-th rod chamber 41 is matched with the M-th rodless chamber 42 to extend or retract a piston rod of the M-stage piston assembly 40, the open end of the first rodless chamber 22 is spaced apart from and not communicated with the M-th rodless chamber 42, and is respectively communicated with two rodless chamber oil passages spaced, the first rod chamber 21 and the Mth rod chamber 41 are distributed at intervals and are not communicated with each other, and are respectively communicated with two rod chamber oil passages distributed at intervals.

In other words, a chamber 11 is provided inside the cylinder 10 and at least two-stage piston assemblies are nested in the chamber 11, the first-stage piston assembly 20 divides the inside of the chamber 11 into a first rod chamber 21 and a first rod chamber 22, while an mth-stage piston assembly 40 is further installed in the chamber 11, the mth-stage piston assembly 40 being provided with an mth rod chamber 41 and an mth rod chamber 42. The first rodless cavity 22 and the Mth rodless cavity 42 are distributed at intervals and are not communicated with each other, the first rod-containing cavity 21 and the Mth rod-containing cavity 41 are distributed at intervals and are not communicated with each other, the rodless cavity oil passages corresponding to the first rodless cavity 22 and the rodless cavity oil passages corresponding to the Mth rodless cavity 42 are distributed at intervals and are not shared, and the rod-containing cavity oil passages corresponding to the first rod-containing cavity 21 and the rod-containing cavity oil passages corresponding to the Mth rod-containing cavity 41 are distributed at intervals and are not shared. After the first-stage piston assembly 20 lifts the mold moving frame to a designated position, the piston rod of the M-stage piston assembly can be kept in the original position and is convenient for mold changing because the M-stage piston assembly 40 can be controlled to have no oil inlet and oil return.

Therefore, according to the utility model discloses multistage cylinder 100 has pole chamber 41 interval distribution and does not communicate through setting up first pole chamber 21 and M, and the pole chamber oil circuit that has that first pole chamber 21 corresponds has pole chamber oil circuit interval distribution and not share with that M has pole chamber 41 to correspond. According to the scheme, multi-stage oil ways can be effectively distinguished, in the using process, when the first-stage piston rod extends outwards to lift the mould moving frame to a specified position, the piston rod of the M-th-stage piston assembly can keep in-situ and does not need a displacement sensor to monitor the real-time position of each stage of piston rod, accurate positioning is facilitated, and the mould changing cost is low.

According to the utility model discloses an embodiment, N is the integer more than or equal to 3, N level piston assembly is including the S level piston assembly 30 that is located between first order piston assembly 20 and the M level piston assembly 40, wherein 1 < S < M, S level piston assembly 30 is equipped with S level and has pole chamber 31, S level has pole chamber 31 and first have pole chamber 21 intercommunication and have pole chamber 41 spaced apart distribution with M, first have pole chamber 21 and S level have pole chamber 31 all with same have pole chamber oil circuit intercommunication, S level piston assembly 30 and first order piston assembly 20 share first rodless chamber 22.

That is, an S-stage piston assembly 30 is also disposed between the first and M- stage piston assemblies 20, 40, the S-stage piston assembly 30 being nested outside the M-stage piston assembly 40, and the first-stage piston assembly 20 being nested outside the S-stage piston assembly 30. The S-stage piston assembly 30 is provided with an S-th rod cavity 31 and an S-th rodless cavity, wherein the S-th rod cavity 31 is communicated with the first rod cavity 21, the S-th rodless cavity and the first rodless cavity 22 share the same rodless cavity, when oil is fed from an oil port communicated with the first rodless cavity 22 and the S-th rodless cavity and oil is discharged from an oil port communicated with the S-th rod cavity 31 and the S-th rodless cavity, a piston rod of the first-stage piston assembly 20 and a piston rod of the S-stage piston assembly 30 can extend outwards to the bottom step by step, and a mold moving frame is lifted to a specified position.

As shown in fig. 1, in some embodiments of the present invention, N is equal to M, that is, a three-stage piston assembly is disposed in the cylinder body 10, and the first-stage piston assembly, the second-stage piston assembly and the third-stage piston assembly are disposed in sequence from outside to inside. That is, the mth stage piston assembly 40 is a third stage piston assembly, the mth rod chamber 41 is a third rod chamber, the mth rodless chamber 42 is a third rodless chamber, the S stage piston assembly 30 is a second stage piston assembly, the S rod chamber 31 is a second rod chamber, and the first rodless chamber 22 and the second rodless chamber are the same rodless chamber. One end of the first-stage piston assembly 20 is inserted into the chamber 11 and is movable along the axial direction thereof, a first rod cavity 21 is fitted between the outer wall surface of the piston rod of the first-stage piston assembly 20 and the inner wall surface of the cylinder 10, and the first-stage piston assembly 20 is provided with a first channel 24 extending along the axial direction thereof.

The multistage oil cylinder 100 further comprises an inner cylinder barrel 50, the inner cylinder barrel 50 is inserted into the first channel 24 and extends along the axial direction of the first channel, the inner cylinder barrel 50 is provided with a second channel 51 extending along the axial direction of the inner cylinder barrel, a second-stage piston assembly capable of moving along the axial direction is inserted in the second channel 51, a first rodless cavity 22 is defined between the piston end of the second-stage piston assembly and the inner wall surface of the inner cylinder barrel 50 in a matched mode, a second rod cavity is defined between the outer wall surface of the piston rod of the second-stage piston assembly and the inner wall surface of the inner cylinder barrel 50 in a matched mode, the second-stage piston assembly is provided with a third channel 33 extending along the axial direction of the second-stage piston assembly, a third-stage piston assembly capable of moving along the axial direction of the third channel 33 is inserted in the third channel, a third rod cavity is defined between the outer wall surface of the piston rod of the third-stage piston assembly and the inner wall surface of the.

That is, as shown in fig. 1, when the multistage cylinder 100 is a three-stage cylinder, the first-stage piston assembly 20 is inserted into the chamber 11 of the cylinder body 10, and the first rod chamber 21 is defined between the inner wall surface of the cylinder body 10 and the first-stage piston assembly 20. An inner bore 50 is inserted within the first passage 24 defined within the first stage piston assembly 20. A second-stage piston assembly is inserted into a second channel 51 defined in the inner cylinder 50, a second rod cavity is defined between the outer wall surface of the piston rod of the second-stage piston assembly and the inner wall surface of the inner cylinder 50 in a matching manner, and a first rodless cavity 22 is defined between the end of the piston of the second-stage piston assembly and the inner wall surface of the inner cylinder 50 in a matching manner. An annular cavity can be formed between the first-stage piston assembly 20 and the inner cylinder 50, and the first rod cavity and the second rod cavity are communicated with each other. A third-stage piston assembly is inserted into a third channel 33 defined in the second-stage piston assembly, a third rod cavity is defined by the outer wall surface of a piston rod of the third-stage piston assembly and the inner wall surface of the second-stage piston assembly in a matched manner, and a third rodless cavity is defined by the piston end of the third-stage piston assembly and the inner wall surface of the second-stage piston assembly in a matched manner.

When the oil inlet communicated with the first rodless cavity 22 is filled with oil and the oil outlet communicated with the first rod cavity 21 and the second rod cavity is filled with oil, the piston rod of the first-stage piston assembly 20 and the piston rod of the second-stage piston assembly can extend outwards to the bottom step by step, and the mold moving frame is lifted to a designated position. The piston rod of the third-stage piston assembly can be kept in place, accurate positioning is facilitated, and die change cost is low.

After the die change operation is completed, oil is fed into a third rodless cavity corresponding to the third-stage piston assembly, oil is fed into a third rod cavity corresponding to the third-stage piston assembly, a piston rod corresponding to the third-stage piston assembly extends to the bottom, and the die is lifted to a specified working position.

Furthermore, a rodless cavity oil path communicated with the first rodless cavity 22 is arranged on the cylinder body 10, and the rodless cavity oil path is arranged inside the oil cylinder without an external oil pipe, so that the space can be saved.

In some embodiments of the present invention, according to the present invention, the multistage oil cylinder 100 further includes: the first guide sleeve 60 is arranged at the opening end of the first guide sleeve 60 and is provided with a first mounting hole which is communicated along the axial direction of the cavity 11, one end of the first-stage piston assembly 20 penetrates through the first mounting hole and extends into the cavity 11, the first guide sleeve 60 is provided with a first oil port 62 and a second oil port 63, the first oil port 62 is communicated with a rodless cavity oil way corresponding to the first rodless cavity 22, and the second oil port 63 is communicated with the first rod cavity 21 and the second rod cavity respectively. Through setting up first hydraulic fluid port 62 and second hydraulic fluid port 63 on first uide bushing 60, make it establish the oil circuit inside the hydro-cylinder, save space reduces use cost.

Optionally, an O-ring is added between the first guide sleeve 60 and the cylinder 10 for sealing, so as to ensure no leakage and improve the sealing performance.

According to the utility model discloses an embodiment is equipped with at least partly first through-hole 23 parallel with the axis of cavity 11 on the rodless chamber oil circuit that corresponds with first rodless chamber 22, can further improve holistic structural integrity and the compactedness of device, does not need external oil pipe simultaneously, has reduced use cost.

Further, the piston rod of the third stage piston assembly is provided with a second through hole 43 penetrating in the axial direction thereof, and the second through hole 43 is formed as at least a part of the rodless chamber oil passage corresponding to the third rodless chamber.

In some embodiments of the present invention, according to the present invention, the multistage oil cylinder 100 further includes: and the second guide sleeve 70 is arranged at the opening end of the chamber 11 and is provided with a second mounting hole which is communicated along the axial direction of the chamber 11, one end of a piston rod of the third-stage piston assembly penetrates through the second mounting hole and extends into the third channel 33, and the second guide sleeve 70 is provided with a third oil port 72 communicated with the third rod cavity. Through with hydraulic fluid port reasonable setting on the uide bushing, both can reduce use cost, effectively distinguish the oil circuit at different levels simultaneously, make its control more accurate.

In some embodiments of the present invention, according to the present invention, the multistage oil cylinder 100 further includes: the flange 80 is arranged on one side, back to the cylinder body 10, of the second guide sleeve 70, the flange 80 is provided with a third mounting hole which is communicated along the axial direction of the cavity 11, one end of a piston rod corresponding to the third-stage piston assembly sequentially penetrates through the third mounting hole and the second mounting hole and then extends into the third channel 33, the flange 80 is provided with a fourth oil port 81, and the fourth oil port 81 is communicated with the second through hole 43. The oil ports are fixed through the flange 80 and are formed in the flange, so that various levels of oil ways can be distinguished conveniently.

The following specifically describes the working process of the multi-stage oil cylinder 100 according to the embodiment of the present invention:

as shown in fig. 1, when the first oil port 62 is filled with oil, the second oil port 63 is filled with oil, the piston rod of the first-stage piston assembly 20 and the piston rod of the second-stage piston assembly extend to the bottom step by step, and the mold moving frame is lifted to a designated position. Since the first rodless chamber 22 is not in communication with the third rodless chamber, the piston rod of the third stage piston assembly does not extend, and a mold change operation can now be performed.

After the mold changing operation is completed, the fourth oil port 81 is filled with oil, the third oil port 72 is filled with oil, the third-stage piston assembly extends to the bottom in a corresponding piston rod mode, and the mold is lifted to a specified working position.

Because the first rodless cavity 22 is not communicated with the third rodless cavity, the first rod cavity 21, the second rod cavity and the third rod cavity are not communicated, and the first-stage piston assembly, the second-stage piston assembly and the third-stage piston assembly are controlled separately, misoperation cannot be caused, and mold changing is not influenced.

In summary, according to the utility model discloses multistage cylinder 100, through making first order piston assembly 20, the entering of second level piston assembly, go out the oil circuit sharing, the entering of third level piston assembly, go out the oil circuit and the entering of first order piston assembly 20 and second level piston assembly, go out the oil circuit separation, after first order piston assembly 20 and second level piston assembly removed the frame with the mould and lift the assigned position, because third level piston assembly did not carry out the oil feed and produce oil, the piston rod that third level piston assembly corresponds keeps the normal position motionless, not only convenient retooling, and also need not displacement sensor to monitor the real-time position of every grade piston rod, and is with low costs. According to the utility model discloses multistage cylinder can make first order piston assembly, second level piston assembly and tertiary piston assembly can the separation control, has compact structure, installation space little, be favorable to accurate positioning and retooling advantage such as the cost is lower.

According to the utility model discloses engineering machine tool, because according to the utility model discloses multistage cylinder 100 of embodiment has above-mentioned technological effect, consequently, according to the utility model discloses engineering machine tool also has above-mentioned technological effect, promptly in the use, can effectively distinguish the oil circuit, does not need displacement sensor to monitor every grade of piston rod real-time position, is favorable to accurate positioning and retooling cost lower.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims (10)

1. A multi-stage cylinder, comprising:

a cylinder defining a chamber extending axially therein, the chamber having an open end;

the piston assembly comprises a cavity, an N-stage piston assembly, a first rodless cavity, an M-stage piston assembly, an M-stage rodless cavity, a first rodless cavity and a second rodless cavity, wherein the N is an integer larger than or equal to 2, the N-stage piston assembly is arranged in the cavity and comprises a first-stage piston assembly and an N-stage piston assembly which are sequentially nested from outside to inside, the first-stage piston assembly is provided with the first rodless cavity and the first rodless cavity, the first rodless cavity is matched with the first rodless cavity so that a piston rod of the first-stage piston assembly extends out or retracts into the opening end, the M-stage piston assembly is provided with the M-stage rodless cavity and the M-stage rodless cavity, M is an integer smaller than or equal to N, the M-stage rodless cavity is matched with the M-stage piston assembly so that a piston rod of the M-stage piston assembly extends out or retracts into the opening end, the first rodless cavity and the M-stage piston assembly are respectively communicated with two rodless cavity oil passages, and are respectively communicated with two oil passages with rod cavities which are distributed at intervals.

2. The multi-stage cylinder according to claim 1, wherein N is an integer greater than or equal to 3, the N-stage piston assembly includes an S-stage piston assembly located between the first-stage piston assembly and the M-stage piston assembly, wherein 1 < S < M, the S-stage piston assembly is provided with an S-stage rod cavity, the S-stage rod cavity is communicated with the first rod cavity and is spaced apart from the M-stage rod cavity, the first rod cavity and the S-stage rod cavity are both communicated with the same rod cavity oil passage, and the S-stage piston assembly and the first-stage piston assembly share the first rodless cavity.

3. The multi-stage cylinder according to claim 2, wherein N is equal to M, the mth-stage piston assembly is a third-stage piston assembly, the mth rod cavity is a third rod cavity, the mth rodless cavity is a third rodless cavity, the S-stage piston assembly is a second-stage piston assembly, the S rod cavity is a second rod cavity, one end of the first-stage piston assembly is inserted into the cavity and is movable in the axial direction thereof, the first rod cavity is fitted between an outer wall surface of a piston rod of the first-stage piston assembly and an inner wall surface of the cylinder body, and the first-stage piston assembly is provided with a first passage extending in the axial direction thereof; the multistage hydro-cylinder still includes:

the inner cylinder barrel is inserted in the first channel and extends axially along the first channel, the inner cylinder barrel is provided with a second channel extending axially along the inner cylinder barrel, the second channel is internally inserted with a second-stage piston assembly capable of moving axially along the second channel, the first rodless cavity is defined between the piston end of the second-stage piston assembly and the inner wall surface of the inner cylinder barrel in a matching manner, the second rod cavity is defined between the outer wall surface of the piston rod of the second-stage piston assembly and the inner wall surface of the inner cylinder barrel in a matching manner, the second-stage piston assembly is provided with a third channel extending axially along the second-stage piston assembly, the third-stage piston assembly capable of moving axially along the third channel is inserted in the third channel, the third rod cavity is defined between the outer wall surface of the piston rod of the third-stage piston assembly and the inner wall surface of the second-stage piston assembly in a matching manner, and the third rod cavity is defined between the piston end of the third-stage piston assembly and the inner wall surface Three rodless cavities.

4. The multi-stage cylinder according to claim 3, wherein said cylinder body is provided with said rodless chamber oil passage communicating with said first rodless chamber.

5. The multi-stage cylinder according to claim 4, further comprising:

the first guide sleeve is arranged at the opening end and is provided with a first mounting hole which is communicated along the axial direction of the cavity, one end of the first-stage piston assembly penetrates through the first mounting hole and extends into the cavity, a first oil port and a second oil port are arranged on the first guide sleeve, the first oil port is communicated with the rodless cavity oil way corresponding to the first rodless cavity, and the second oil port is communicated with the first rod cavity and the second rod cavity respectively.

6. The multi-stage oil cylinder according to claim 4, wherein the rodless chamber oil passage corresponding to the first rodless chamber is provided with at least a portion of a first through hole parallel to the axis of the chamber.

7. The multistage cylinder according to claim 3, wherein the piston rod of the third stage piston assembly is provided with a second through hole that penetrates in the axial direction thereof, the second through hole being formed as at least a part of the rodless chamber oil passage corresponding to the third rodless chamber.

8. The multi-stage cylinder of claim 7, further comprising:

the second guide sleeve is arranged at the opening end of the cavity and is provided with a second mounting hole which is communicated along the axial direction of the cavity, one end of a piston rod of the third-stage piston assembly penetrates through the second mounting hole and extends into the third channel, and a third oil port communicated with the third rod cavity is formed in the second guide sleeve.

9. The multi-stage cylinder of claim 8, further comprising:

the flange is arranged on one side, back to the cylinder body, of the second guide sleeve and is provided with a third mounting hole which is communicated along the axial direction of the cavity, one end of a piston rod corresponding to the third-stage piston assembly sequentially penetrates through the third mounting hole and the second mounting hole and then extends into the third channel, and a fourth oil port is formed in the flange and is communicated with the second through hole.

10. A working machine comprising a multi-stage cylinder according to any one of claims 1-9.

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